# -*- coding: utf-8 -*-
# @Time    : 2023/11/12
# @Author  : Yangyali
#
import pygame
from pygame.sprite import Sprite


class Bullet(Sprite):
    """管理飞船所发射子弹的类"""

    def __init__(self, ai_game):
        """在飞船当前位置创建一个子弹对象"""
        super().__init__()
        self.screen = ai_game.screen
        self.settings = ai_game.settings
        self.color = self.settings.bullet_color

        # 在(0,0)创建一个表示子弹的矩形，再设置正确的位置.
        self.rect = pygame.Rect(0, 0, self.settings.bullet_width,
                                self.settings.bullet_height)
        self.rect.midtop = ai_game.ship.rect.midtop

        #存储用小数表示的子弹位置.
        self.y = float(self.rect.y)

    def update(self):
        """Move the bullet up the screen."""
        # Update the decimal position of the bullet.
        self.y -= self.settings.bullet_speed
        # Update the rect position.
        self.rect.y = self.y

    def draw_bullet(self):
        """Draw the bullet to the screen."""
        pygame.draw.rect(self.screen, self.color, self.rect)
